Electronic counter



June 30, 1953 TENS TRANSFER OUTPUT J. R. DESCH 2,644,111

ELECTRONIC COUNTER Filed Dec. 4, 1951 INVENTOR JOSEPH R. DESCH HISATTORNEYS Patented June 30, 1953 ELECTRONIC COUNTER Joseph R. Desch,Dayton, Ohio, assignor to The National Cash Register Company, Dayton,Ohio, a corporation of Maryland Application December 4, 1951, Serial No.259,856

14 Claims.

This invention relates to a novel electron tube counting circuit and inparticular to a circuit employing negative-grid thyratrons which areconnected in a ring or chain for sequential operation one after anotherin response to input impulses.

The principal advantages of the novel circuit lie in its simplicity dueto the elimination of many resistors and capacitors which had heretoforebeen required and in the consequent simplification in its fabrication.

In prior circuits using negative-grid thyratrons, it had been usual tohave individual cathode resistors and bias supply and priming resistancenetworks for each of the tubes of the ring or chain, as well asindividual input capacitors and capacitors in the extinguishing circuitsfor these tubes. The novel circuit does away entirely with biassupplying and priming resistance networks for the tubes of the ring orchain; does away with input capacitors and extinguishing capacitors forthe tubes of the ring or chain; and reduces the number of cathoderesistors which are required.

Briefly, the novel circuit utilizes negative-grid thyratrons of thetetrode type having at least an anode, a cathode, a control grid, and ashield grid. The tubes of the ring or chain are divided into twooperational groups, with the cathodes of the tubes of each groupconnected together and to ground over a resistor which is common to thetubes of the group and with the anodes of each group connected togetherand over a resistor to a separate source of anode potential for eachgroup.

The tubes are connected into an operative chain by floating connectionsbetween the tubes, which connections extend from, the shield grid of atube of one group to the control grid of a tube of the other group. Incase of a ring, the shield grid of the last tube in one group will beconnected to the first tube in the other group. In the novel circuit,the shield grids serve as probe electrodes whereby the conductingcondition of a tube can be utilized to control another tube. Thesefloating connections cause the sequential operation of the tubes to takeplace in the desired order by enabling the shield grid or probeelectrode in a conducting tube to so influence the control grid of thenext tube in the sequence that the next tube will conduct when the nextinput impulse is received by the circuit.

The anode potentials for the two groups of tubes are derived from apotential control means which can be operated alternately to one or theother of two stable operating conditions. The anode 2 potentials arederived from the control means in such a manner that they can vary withthe different operatin conditions of the means. When the control meansis in one operating con-- dition, the anode potential which is suppliedto one of said groups of tubes will be high enough to cause conductionin a tube of that group; but,

when the control means is in its other condition,

the anode potential which is supplied to this one group of tubes willhave been reduced to a value which will not support conduction in thetubes of the group. In a similar manner, the anode potential which issupplied to the other group of tubes will be high or low, depending onthe operating condition of the control means. The relation between theanode potentials which are supplied to the two groups of tubes is suchthat, whenever the high anode potential is supplied to one group oftubes, the low potential will be supplied to the other group of tubes.-

The input impulses for causing the step-bystep operation of the tubes ofthe chain or ring are applied to the control means, each impulse beingeffective to reverse the operating condition of the control means andthereby cause the abovenoted variation in the potentials supplied to theanodes of the tubes of both groups.

In the novel circuit, therefore, the combination of the grouping of thetubes and the variation of the anode potentials applied to the groupsfrom the control means, together with the floatingshield-grid-control-grid connections which connect the tubes in a chainor ring, enable the tubes of the chain or ring to be operated one at atime in sequence in response to input impulses which are applied to thecontrol means.

If the tubes are connected in a ring and a plurality of rings are to beused for forming a mum-denominational order accumulator, suitableoutput-signal-generating means can be utilized as tens transfer meansbetween adjacent orders to cause a unit to be entered in the higherorder when the lower order exceeds its capacity.

Furthermore, if desired, controls can be supplied :for causing aparticular tube to conduct to prepare the ring or chain for step-by-stepoperation.

It is an object of the invention, therefore, to protvide a simplifiedelectron tube counting circu1 A further object of the invention is toprovide a negative-grid. thyratron counting ring in which negative biassupp-1y and priming resistance networks can be eliminated, therebyrequiring fewer impedance elements in the circuit.

A further object of the invention is to provide a novel negative-gridthyratron counting ring which has a simplified circuit and will beeasier to construct.

With these and incidental objects in View, the invention includescertain novel features of construction and combinations of parts, apreferred form or embodiment of which is hereinafter described withreference tothe drawing which accompanies and forms a part of thisspecification.

Of the drawing:

Fig. l is a circuit diagram of one of thenovel counting rings which iscapable of formingone denominational order of an accumulator, includingprovisions for presettingthe ring to -a.pre-- determined condition andalso including provisions for controlling an output-signal-generatingmeans which may be used to furnish tens transfer to a higher order ofthe accumulator.

Fig. 2 shows a modified form of trigger pair for supplying anodepotentials to the ring.

Detailed description In order that the invention may be more clearlyexplained, it will be described as embodied in a counting ring which issuitable for use as a denominational order of a decimal accumulator. Itis to be understood that the invention is not limited to its use as acounting ring. or to the use of ten tubes in the ring, because it issusceptible of use wherever sequential operation of tubes is desired andwith diiferent numbers of tubes in the ring, the only limitation" beingthat, when connected to operate :as a ring, an even numberof tubes beprovided. It will also become obvious from the following descriptionthat additional tubes can be included in the ring circuit withoutrequiring any additional circuit elements of resistance or capacitance.

In the following description, values'of potential with reference toground and values of resistance and capacitance, as well as tube types;will be given. It is not intended that the inven tion be limited tothese particular potentials or to the values ofresistance-specifiedherein, because the potentials used'are merelyselected as convenient potentials for the disclosure; and the values ofthe circuit elements of resistance and capacitance given correspond inrelative value to the potentials chosen. It is also obvious'that othertypes of tubes may be used and also-that other potentials may be used,and; when this occurs, the values of the circuit elements can beadjusted accordingly to maintain the properrelationship between thevarious parts "of the circuit. Throughout the drawing, the'heater'elements of the thyratrons are shown conventionally;

The type of tube usedthrough the circuit is the tetrode thyratron of the2051'type, which'has' an anode, an indirectly-heated cathode, a controlgrid, and a shield grid;

Excellent results have been obtained from circuits constructed accordingto theinvention'and using'the values of resistance, capacitance, and,potentials to be given; These circuits also showed good tolerance tovariations in'the positive potentialsupply and in the size of the inputimpulses which were supplied thereto..

The circuit of Fig. 1 includes aring o-f'digitrepresenting tubes, whichtubes are operable step by step in sequenceya pair'of tubes 50" and 5|,which form the control means and operate as a. trigger pair and supplyanode potentials to the. tubes'of the ring; a. pulse-shaping tube 52,upon which input impulses are impressed and from which a strong uniformoperating impulse is sent to the trigger pair for each input impulsewhich it receives; and an output signal tube 53, which may be used forsending an impulse to another order each time the ring exceeds itscapacity when the ring forms one order of an accumulator. In order tosimplify the showing of the circuit, only the 0, 1, 2, 7, 8, and 9*digitrepresenting tubes of the'ring have been shown, because thecircuits and the operation of the 3 to 6 digit-representing tubes arethe same asthose shown and will be clear from those circuits which areshown.

The pulse-shaping tube 52, which is connected in a self-extinguishingcircuit, will conduct momentarily and will be extinguished automaticallyeach time an input impulse is applied thereto. The anode of this tube isconnected over resistor 55, of 2'70 ohms, point 56, and resistor 51, of1.5 megohms, to conductor 58, to which a potential of +150 volts isapplied at terminal 59.

Point: 56in this circuit is connected to ground,

suitable to cause the pulse-shaping tube to con-- duct. Each time thetube 52conducts momentarily in response to an input impulse, thepotential of point 60 will rise sharply to produce: a positive impulse,which impulses will be strong and uniform. These impulses are usedtodrive the trigger pair of the control means from whichthe anodepotentials for the tubes of the ring are derived.

The tubes 50 and 5| of the trigger pair of the control means areconnected in similar. circuits, which enable the tubes to conductalternately in response to positive potential impulses which areimpressed thereon. The anodesof these'tubes are connected directlytoconductor 58, which has +150 volts supplied thereto, and the cathodesof the tubesare connected to ground over resistors "Hi-and H, each of20,400 ohms. The cathodes'of these tubes are also coupled b'y a blow-outcircuit Containing a. resistor 12, of 7,800 ohms, and a capacitor 13, of.003 microfarad, in series. shield grid and the control grid of tube 50are connected together and over point 14 and resistor 15-, of 250,000ohms; to terminal 16, which supplies 12-volt bias potential. Similarly,tube 5| has its shield and control grids connected together and overpoint 71 and resistor 18, of 250,000 ohms, toterminal 16.

When tube 50 is non-conducting; its cathode, due to the high impedanceof the tube, will be' at ground potential, but, when the tube' conducts,the potential of the cathode will rise sharply to about +135 volts, dueto the division of the drops between the tube and resistor 10' in thecathode circuit. This means that point 79 inthe cathode circuit willmake a similar excursion upwardly as the tube begins to conduct anddownwardly as the tube ceases conduction. Similarly, point 80 in thecathode circuit for tube 5| will make a potential excursion upwardlyand. downwardly as that tube begins .to. conduct and ceases to conduct.

Point 63 in this" circuit is The blow-out connection between; tubes 50and 5! insures that only one tube of the. pair will be conducting at atime. -As positive impulses are impressed on the grids of the tubes,they will be ineifective on the .tube that is already conducting butwill cause the non-con-. ducting tube to conduct. Conductionbeginninginthe previously non-conducting tube will .cause.

its cathode potential to rise sharply. This rise is sent as an impulseover thejblow-out circuit to the other tube to cause the previously0011-.

sistor 85, of 100,000 ohms. Each input impulse which is applied to thepulse-shaping tube 52 will cause a positive impulse tobe sent overthiscoupling to cause a reversal in the conducting condition of the tubes ofthetrigger pair.

While the means in the control means which operates to one or anothercondition alternately in response to input impulses is shown as agastube trigger pair, it is to be understood that the invention is notlimited to the use of this particular form of means but can utilize anymeans which can operate to alternate conditions in response to impulsesand can supply the necessary anode potential variations.

The connections involving the tubes of the ring are extremely simple andrequire very few circuit elements of resistance and capacitance.

These tubes are connected into two operational groups and are alsoconnected for sequential operation. The anodes of the evendigit-representing tubes to 8 are connected together and over a resistor90, of 22,000 ohms, to point 19 in the cathode circuit of trigger tube50, from which they will be supplied with a high potential which willpermit conduction in a tube in the group when tube 50 conducts but fromwhich they will be supplied a low potential which will not supportconduction in a tube in the group when trigger tube 50 is notconducting. Similarly, the anodes of the odd digit-representing tubes 1to 9 are connected together and over a resistor 9|, of 22,000 ohms, topoint 80 in the cathode circuit of trigger tube and will be suppliedwith a high potential which will permit conduction in a tube in thegroup when trigger tube 5! conducts but will be supplied with a lowpotential which will not support conduction in a tube in the group whentrigger tube 5| is not conducting.

Since only one tube of the trigger pair conducts at a time, only one ofthe groups of tubes of the ring at a time will be supplied with highpotential.

The cathodes of the even digit-representing tubes are connected togetherand over point 92 and the common resistor 93, of 22,000 ohms, to ground.The connection of the cathode of the 0 digit-representing tube of thegroup to the point 92 is over point 94 and an additional resistor 95, of33,000 ohms, which enables the oathode of the 0 tube to have a potentialwhen the 0 tube conducts which is distinctive from that when any othereven tube conducts. This distinction in potential is used to controltheoperation of a transfer tube in a manner to-be explained more fullyhereinafter. The cathodes of the odd digit-representing tubes areconnected together and over the common resistor 96, of 22,000 ohms, toground.

The connections between the tubes .of. the ring by which sequentialoperation-is obtained are extremely simple and extend from the shieldgrid or probe electrode of atube inone group directly to the controlgrid of thetubein the, other group which is next to be operated. As, anexample, the shield grid or probe electrode of the 0 tube of the evengroup is directly connected to the control grid of the 1? tube of theodd group, and the shield grid or probe electrode of the 1 tube of theodd groupisdirectly connected to the control grid of the 2 tube of theeven group, etc. The connection of the tubes in aring is completed byconnecting the shield grid or probe electrode of the 9 tube to thecontrol grid of the 0 tube. In the ring circuit as shown, the shieldvgrid in a conducting tube will be more positive than the control grid,and this condition is utilized to obtaindirectional control in thesequential operation of the tubes and cause tube which has its controlgrid connected to a shield gridof a conducting tube to be fired beforethe tube which has its shieldgrid connected to the control grid of theconducting tube when highanode potential is supplied to thenon-conducting, group ofv tubes. 7 I

It is to be particularly noted that, while the tubes of the ring are ofthe negative-grid .thyratron type, there are no negative bias supply andpriming resistance networks provided for these tubes, the onlyconnection to thecontrol grids of any of these tubes being the floatingdirect connection to the shielding grid orprobe electrode of the nextpreceding tube inv the ring; and that addition of tubes to the ring doesnot require the use of any more resistors or capacitors. I 1

Provision has been made for presetting the circuit to a startingcondition, which in the instant embodiment will be that condition inwhich the 0 tube of the ring willgbe conducting. The circuit whichconnects the anodes of the even tubes has a switch I00 therein, which isnor mally closed but which can be opened in a pre: setting operation toprevent the application of anode potential to any of the evenf tubesexceptthe 0 tube. With the switch loll-open, the tri ger pair isoperated to cause tube 50 to conduct. This supplies high anode potentialto the 0 tube only, which will conduct, After the 0- tube has beenrendered conducting, the switch I00 is closed to supply anode potentialto the remaining even tubes, and the ring is ready for normal operation.With the 0 tube conducting, the drops across the anode resistor and thecathode resistors 93 and 95-will reduce the anode-cathode potentialapplied to theother even tube to a valuethat will prevent :initiation'of conduction in anyof theother feven tubes when theswitchlliflisclosed.I

Trigger'tubes 50 ,canJbe firedin the presetting operation by groundingitscontrol grid or by applying a positive impulse to/the. grid. l Onemeansfor applying positive potential to the grid is shown inFig. l andconsists of; a capacitor 10!, of .01 microfarad, .which has '.:one "sidegrounded and which. has a lead-.102 connected tothe; other side. Thisle'adJllZ can. bestouched to the. conductor 58 to. charge {the capacitorllll and canrthen' beitouchede to point 103, whichzis' connected to thecontrol gridsoftube50; to apply apositive impulse to this tube;

Any: suitable outputimeans canbe controlled Theioutput tube 53 hasitsanode connected over point I05Land:resistor I06, of 1 megohm,t'oconductor 58, which has +150 volts applied thereto. Point I05-isconnectedto ground over a capacitorv of .005 microfarad. The cathode isconnected to ground Over point I! and resistor I08, of 68.000ohms, inparallel with capacitor I 09} of ;001 microfa'rad.'

Theishieldgrid and control grid of the output tube 53-are connectedtogether and over a point H0; resistor: III; of 1- m'egohm, to the9-volt--bias'supp1yterminal I I2. Point I I I0" in this: circuit iscoupled over a capacitor I I 3; of l00 micr'o-microfarads, to anadjustable tap on a 1-megohma potentiometer II4, which is connectedbetween ground and point 94 inthecathode circuitof' the-'O tube. Due tothe resistor 95 in the cathode circuit and the coupling of point fltoground over the potentiometer I I4, point 94'-will-be-more'positivewhen the 0 tube conductsthanwh'en any of the other even tubes conduct;Thetap on the potentiometer is adjusted sothat the output tube 53wil1conduct momentarily each time the 0' tube becomesconducting, but willnot conduct'when' any of the other even tubes becomes conducting.

Eachtime the output tube 53 conducts, the potential of point I01 in itscathode circuit will rise, and this rise is transmitted over a suitablecapacitor II as'an output impulse which can beusedtocause a unit valueto be entered in the higher'or-der. A suitable switch can be include'dinthe outputcircuit, to be opened during presetting to prevent anyundesirable output impulses-from being sent out during presetting as aresult of firing the"0 tube.

It isto be understood that the output signal means which is disclosedherein is merely illustrative'andthat other forms which canbeoperated'orxc'onditionedby' positive impulses can also be used withthe novel ring;

Inathe circuitiof Fig, 1, the anode potentials for the two groups oftubes of the ring are derived'from the cathodesof the'tri'gger'pair, butthe invention is not limited to this arrangement. In Fig. 2 is shownamodified-form of trigger- Dair in which anode potentials are derivedfrom the anodes of the tubes of the pair; The trigger p'air of Fig; 2can replace'the trigger pair which is-enclosed in the dot-and-dashoutline'in Fig. 1, the:conne'ctions|a, b, c, d, e, and from the dot-'and-dash outline in both figures being the same; In the trigger pair ofFig. 2, the'tubes I and I 2| have .theiranodes connected over resistorsI 22 and. I23, each of 20,400 ohms, and over connections (1 and b to thepositive potential supply conductor (as 58 in-Fig. 1') and have theiranodes coupledbya blow-out capacitor I24, of .01 microfarad; Thecathodes of the tubes 7 are grounded, and their shield grids andcontrolgrids are connected :together: and oven connections e 8 3 and ifztoitheir. bias i supply and input couplings to the-:pulse-shaping tube(as52in Fig. 1).

The anode of .tube I20 is connected over resistor I25; of: 10,000? ohms;and connection it to the anodes ofxthe even digit-representing tubes ofthe ring; The anodes of this group of tubes of the ring will have ahighpotential applied theretowhen tube I 20 is non-conducting and a lowpotential when tube I20 conducts. Similarly, the anode of tube lfl isconnected'over resistor I26, of-10,00'0 ohms','.to the'anodes of the oddgroup of tubes of the ring and will supply a high potential to the tubesof this group when it is noncon'ductingand a low potential when it isconducting. When the trigger pair'of Fig. 2 is in-- corporated inthecircuit of-Fig'. 1 to replace the trigger" pairshown therein, avoltage of about +300 volts -is applied to terminal-59, andin-presetting the ring'to zero condition the right-handtube of -thetriggerpair tube I2] is rendered con"- ducting. Otherwise the circuitconstants and operation of'the circuitare'the same as when'the triggerpair of Fig; 1 is used in the circuit.

While'only' two forms of trigger pairs are shown as control means forsupplying desired anode potentials to the groups oftubes of the ring,other" formsof trigger pairs also may be used; all that is required isthatthey be capable of furnish-- ing the necessary potential variationsat two pointsin their circuit from which the potentials for thetwogroupsof tubes can' be-derived.

Operation The operations will be explained with reference to'thexcircuit of s Fig. 1'.

With. the variousoperating and bias potentials appliedand' withthe-cathodes properly heated, the circuit may be set in itszero-condition by opening: switch I00 in the'anode circuit for the evengroup of tubes: and by touching the lead I02 first to conductor 58 andthen to point I03 to fire tube 50 0f the trigger pair. As tube 50-conducts, its cathode;potential will be high; and thiszwill supply thehigh anode: potential to the 0 digit-representing} tube of the ring.After the "0 tube conducts; theswitch I00-is closed to supply anodepotential'to the other tubes-of the even group. When the"0" tube isconducting, the drop-across-thetube-will bejust enough to sustainconductionbut will 1 not be high enough to initiate conduction in a.tube; hence, when switch I00 is closed after the0" tube is conducting,none of the other even tubes will begin to conduct;

When trigger tube 50 was fired, it caused. trig.- gertube -51 to beextinguished, if it were the first tube to. conduct when potential wassupplied. With tube 5I'non-cond-ucting, it will supply low anodepotential to all the odd tubes, and all of these tubeswill benon-conducting.

At the end of'the presetting. operation, the -"0 tube of 'the ring. andthe triggertube 50' will'be conducting.

. It will be recalled that the digit-representing tubes are conhectedina ring by floating direct connections between the shield grid or probeelectrode'ofa tube in one groupv andthe control grid of atube in"theiother group. This means that the shield 'grid'or probeelectrodeofthe 0'tube in theeven groupis connected to the control gridof "tlie'fTtube'in'the odd group; the shield grid or'prob'e electrodeof the 1 tubeof the odd group "is 'con'nectedto the"2 tub'ein' the even" group? etc.

* When-"a tube-conducts: its shieldgridorprobe electrode, being in theionized medium; will become more positive and will cause the controlgrid of the next tube in the ring, to which it is directly connected, tobecome more positive. Hence, with the tube conducting, the control gridof the 1 tube will be the only one connected to a Shield grid or probeelectrode in a conducting'tube and will be more positive than the rest.

The first impulse from'the impulse source 67 will cause thepulse-shaping tube 52 to operate and send a strong positive impulse tothe trigger pair to reverse its operating status. As tube 5! is firedand becomes conducting, its cathode potential will rise from the lowtothe high value,

and during this rise the 1 tube will be rendered conducting firstbecause its control grid was more positive than that of any of the otherodd group tubes. As soon as the 1. tube begins to conduct,

the drop across resistors 9! and 96 will reducethe voltage across thetube sufliciently to prevent any other odd group tube from firing.v",Only the 1 tube in the odd group will be conducting. The potentialrise of the cathode of tube 5| is impressed across the blow-outcapacitor 13 and the resistor "12 and'on the cathode of tube 59 to causetube 56 to be extinguished in the wellknown manner. As tube 50 isextinguished, the potential of its cathode will drop from'its high valueto its low value, and conduction can no longer be supported in the 0tube, which will be extinguished.

The next input impulse on tube 52 will cause another reversal of theoperating status of the trigger pair, and, since the'control grid of the2 tube is more positive than'any of the other even group tubes, thistube will conduct. The reversal of the trigger pair wil1 apply the lowpotential to the odd group of tubes and will extinguish the 1 tube. 7Additional impulses will cause the reversal of the trigger pair to bringabout the step-by -step operation of the other tubes in the ring, the ?9tube preparing the. 0 tube {or operation as the next tube of thesequence. With the operation of the 0 tube, the cycle starts all overagain.

When the 0 tube conducts, its cathode potential rise is impressed on thegrids of the tens transfer tube 53 to cause this tube to be fired andgenerate a tens transfer output impulse, which,

in operations other than presetting, can be impressed on suitableapparatus to cause an operation thereof.

While the circuits shown and described herein are admirably adapted tofulfill the objects primarily stated, it is to be understood that it isnot intended to confine the invention to the embodiments hereindisclosed, for it is susceptible of embodiment in various other forms.

What is claimed is:

1. In a device of the class described, the combination of a firstplurality of electron tubes; a second plurality of electron tubes; saidtubes be ing 01' the negative-grid thyratron type, each having at leastan anode, a cathode, a probe electrode, and a control electrode; a firstcommon anode-cathode potential supply connected to the first pluralityof tubes and forming them into a first operational group; a secondcommon anodecathode potential supply connected to the second pluralityof tubes and forming them into a second operational group; means tocontrol said first and second potential supplies to provide a high anodepotential to one group to cause conduction in a tube of that group andat the same time a from the probe electrode of a tube in one group tothe control electrode of a tube in the other group; and input means forcausing an operationoi the potential supply control means to reverse thehigh and low conditions of the anode potential supplied to the groups;the supplying oi anodecathode potentials in two groups and the varyingof their anode potentials in response to impulses together with theserial connections between tubes, causing the tubes to be operated oneat a time in sequence.

2. The device as claimed in claim 1 in which the connections to thecontrol electrodes of the negative-grid thyratron tubes are floatingconnections and do not include any negative bias supply resistancenetwork.

3. The device as claimed in claim 1 in which the connections connectingthe tubes in the operational series are simply conductors and do notinclude impedance elements.

4. The device as claimed in claim 1 in which the anode-cathode supplyfor each group of tubes includes an anode resistance and a cathoderesistance which are common to all the tubes or" the group.

5. The device as claimed in claim 1 in which the anode-cathode potentialsupply for each group includes'an anode resistance and a cathoderesistance which are common to all the tubes of the group and in whichthe series connections between the tubes are direct connections which donot include any resistors or capacitors, whereby an extremely simplering is provided.

fifThe'device as claimed in claim 1 in which the means for controllingthe potential supplies is operable alternately to one or another of twostables states of operation and includes a potential supplyingresistance network, said network in one of said states supplying highpotential to the first group and low potential to the second group andin the other of said states supplying low potential to the first groupand high potential to the second group.

'7. The device as claimed in claim 6 in which the means for controllingthe potential supplies includes a trigger pair in said resistancenetwork, said trigger pair being operable alternately to one and theother of said stable states in response to input impulses.

8. In a device of the class described, the combination of a plurality ofdigit-representing electron tubes of the negative-grid thyratron type,each tube having at least an anode, a cathode, a probe electrode, and acontrol grid; a common anode-cathode potential supply connected to allthe odd digit-representing tubes and forming them into an operationalgroup; a common anodecathode potential supply connected to all the evendigit-representing tubes and forming them into an operational group;means to control the potential supplied by the two potential supplies tocause the potential at each supply to vary between a high anodepotential which will cause a tube to conduct and a low anode potentialwhich will prevent conduction in a tube and to further control thepotential supplies so that when high potential is supplied to the eventubes, low potential will be supplied totthe odd tubes, and vice versa,said control means operable inuresponse to impulsesand uponeachoperation reversing the high and low anodepotentials supplied to theodd and evenflgroups1of-tubes; means connecting the tubes in digital:sequence, each connection being agfioating connectionand extendingdirectly from the probe'elect-rode of a tube to the control-gridofthe-tube of next higher digital value and eliminating any negative biassupply for the control grid; and-meansto apply input impulses to thepotential supply control means to cause its operation to vary-thepotentials supplied to the ;ring, whereby to cause the sequentialoperation of the tubes '0f';the ring.

9. The device as claimed in claim 87in which an anode resistor and a;.cathode resistor are included in theanode-cathode potential supply ofeach group and are common to the tubes ;of the group; and in which theconnections for connecting the tubes in the-digitalsequence are onlyconductors, whereby a ring requiring-a minimum of resistors is produced.

10. The device as claimed in claim'8-in which the means to control thepotential supplies is a trigger pair having two stable states ofoperation and operable alternately to one and the other of the twostates and including a potential, supplying resistance network forsupplying high potential to the odd groupof tubes and low potentialtothe even group of tubes when the trigger pair is in one of its operatingstates and for supplying low potential to the odd group and highpotential to the "even group when thetrigger pair is in the other of itsoperating states.

11. In a device of the class described, the combination of a pluralityoftubesof the negativegrid thyratron type, each tube including at leastan anode, a cathode, a probe electrode, and a control grid; a circuitconnecting the cathodes of half of the tubes together and over a commonimpedance to a cathode potential supply to form a first group of tubes;a circuit connecting the cathodes of the other half of the tubestogether and over a common impedance to'a cathode potential supply toform a second group of tubes; a circuit connecting the anodes of thefirst group of tubes together and over-a common impedance to a firstsource of'anode potential; a circuitcon- 12 meeting the anodes ofthesecondgroup of tubes together andover acommon impedanceto asec- 0ndsource of anode potential; meansto control an operational series usingtubesfromthe first and second groups alternately in the series, :theseries connections being floating, negative-biasfree connectionsextending directly vfrom jthe probeelectrode of a tube to thecontrolgrid of the next tube in the series; and means for-applying inputimpulses to the anode potentialcontrol means to cause it to operate toreverse the high and low potential supplies each time an impulse isreceived, said reversal of potential conditions together with the seriesconnections, causing the sequential step-by-step operation of the tubesin the ring; said anode circuits and cathode circuits with their commonimpedances, together'with the direct series connections between tubes,enabling a ring to be produced with a minimum of impedance elements.

12. The device as claimed in claim 11 in which the series connectionbetween tubes is merely a conductor and contains no resistors.

13. The device as claimed in claim 11 in which the means for controllingthe potential at two potential sources is operable alternately to one.

or another of two conditions in response to input impulses, said meansin one condition causing the high potential to be applied to the firstgroup and low potential to be applied to the second group and to reversethe high and low potentials when in said'other condition.

14. The device as claimed in claim 13 in-which the means which isoperable to one or another of two conditions is a-trigger pair whichincludes a resistance network which is controlled to supply thepotential variations.

JOSEPH R. DESCH.

No references cited.

